Putty knife



FIG. 1 is a perspective view of a putty knife showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a side elevation view thereof;

FIG. 5 is a side elevation view opposite to that shown in FIG. 4;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines throughout the figures are shown of illustrate portions of the putty knife and form no part of the claimed design. 

CLAIM The ornamental design for a putty knife, as shown and described. 